Because as of now straw polls show they are 3 votes short (same as they were last time around) and one of those votes is the former Dem (as noted by brononick) who wants to be Mayor of Omaha one day if rumors are to be believed. If he wants any shot at that he will not go against the will of those people and they do not want to lose their one EV.
It isn't about integrity...it is about the fact that even GOPers are split on it/against it as are the voters. Nebraska isn't Alabama they don't just fall in line because the Party tells them too. If they did they would have flipped that vote rule the last time this was tried. The fact that an outsider is pushing it like Graham is as likely to turn them off as it is to make them do it.
I also don't think, even if they did find a way to bribe them to do it, that it would hold up in Court just like most election changes this close to the election don't.
Also, remember it only matters if Harris needs it to cross the threshold. She would basically need to only win the Blue Wall States for that to happen. (that creates the 269-269 tie) Any other state she picks up makes it irrelevant. She will win one of AZ, NC or NV. I will leave GA out of this until we know how their lawsuits play out.
